# Weird block on images on read

**URL:** <https://forum.opencv.org/t/weird-block-on-images-on-read/2286>\
**Category:** Python\
**Tags:** imgcodecs\
**Created:** [March 21, 2021, 11:57pm UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286 "2021-03-21T23:57:46Z")\
**Posts on this page:** 9\
**Page:** 1

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**Author:** ![martin\_o](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/martin_o/32/1486_2.png) [@martin\_o](https://forum.opencv.org/u/martin_o)\
**Post date:** [March 21, 2021, 11:57pm UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/1 "2021-03-21T23:57:46Z")

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Hi!  
I am having some weird issues when reading certain files.  
Here is the original image as well as the one opencv saves (Latter is the one with the orange block on it). I don’t know why it saves with a big orange block on it.  
Code is only this:  
[opencvtest - Pastebin.com](https://pastebin.com/YL2BmXhm)

Image: [Imgur: The magic of the Internet](https://imgur.com/a/dh4Lm5q)

Thanks for any help!

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**Author:** ![laurent.berger](https://avatars.discourse-cdn.com/v4/letter/l/ec9cab/32.png) [@laurent.berger](https://forum.opencv.org/u/laurent.berger)\
**Post date:** [March 22, 2021, 7:41am UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/2 "2021-03-22T07:41:42Z")

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Hi,  
You can past your code in your question.  
Is your link good?

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<div class="post-metadata">

**Author:** ![martin\_o](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/martin_o/32/1486_2.png) [@martin\_o](https://forum.opencv.org/u/martin_o)\
**Post date:** [March 22, 2021, 8:01am UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/4 "2021-03-22T08:01:44Z")

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Code is:

```
import numpy as np
import cv2
cv2.imwrite("testplain.png", im)
```

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<div class="post-metadata">

**Author:** ![martin\_o](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/martin_o/32/1486_2.png) [@martin\_o](https://forum.opencv.org/u/martin_o)\
**Post date:** [March 22, 2021, 8:07am UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/5 "2021-03-22T08:07:07Z")

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I saw that the images was missing, added it now

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**Author:** ![berak](https://avatars.discourse-cdn.com/v4/letter/b/85f322/32.png) [@berak](https://forum.opencv.org/u/berak)\
**Post date:** [March 22, 2021, 8:11am UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/6 "2021-03-22T08:11:22Z")

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please do NOT use external bins for code or images, put it all HERE, thank you.

(also, imgur is some shit site, blocked in several countries for a good reason…)

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<div class="post-metadata">

**Author:** ![laurent.berger](https://avatars.discourse-cdn.com/v4/letter/l/ec9cab/32.png) [@laurent.berger](https://forum.opencv.org/u/laurent.berger)\
**Post date:** [March 22, 2021, 8:15am UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/7 "2021-03-22T08:15:57Z")

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What is im?  
opencv does not manage transparency. Display results are differents.

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**Author:** ![martin\_o](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/martin_o/32/1486_2.png) [@martin\_o](https://forum.opencv.org/u/martin_o)\
**Post date:** [March 22, 2021, 8:18am UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/8 "2021-03-22T08:18:40Z")

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Hi! Since I am a new user, I cant upload images to post yet.  
Complete code is updated here:  
im = cv2.imread(‘tekst.png’)  
cv2.imwrite(“testplain.png”, im)

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<div class="post-metadata">

**Author:** ![crackwitz](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/crackwitz/32/14_2.png) [@crackwitz](https://forum.opencv.org/u/crackwitz)\
**Post date:** [March 22, 2021, 5:40pm UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/11 "2021-03-22T17:40:04Z")

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> [@laurent.berger](#):
>
> opencv does not manage transparency

this is the key.

your data seems to contain transparency.

if you use OpenCV’s imread and imwrite, you have to **ask** these functions to keep the fourth channel.

if you don’t, the pixels that _would_ be transparent (their RGB values don’t matter), suddenly become opaque, and their RGB values are revealed!

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<div class="post-metadata">

**Author:** ![martin\_o](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.opencv.org/martin_o/32/1486_2.png) [@martin\_o](https://forum.opencv.org/u/martin_o)\
**Post date:** [March 22, 2021, 6:14pm UTC](https://forum.opencv.org/t/weird-block-on-images-on-read/2286/12 "2021-03-22T18:14:41Z")

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This was the solution! Thanks everyone